Yasin Arslan

Determination and interference studies of bismuth by tungsten trap hydride generation atomic absorption spectrometry

The determination of bismuth requires sufficiently sensitive procedures for detection at the microg L(-1) level or lower. W-coil was used for on-line trapping of volatile bismuth species using HGAAS (hydride generation atomic absorption spectrometry); atom trapping using a W-coil consists of three steps. Initially BiH(3) gas is formed by hydride generation procedure. The analyte species in vapor form are transported through the W-coil trap held at 289 degrees C where trapping takes place. Following the preconcentration step, the W-coil is heated to 1348 degrees C; analyte species are released and transported to flame-heated quartz atom cell where the atomic signal is formed. In our study, interferences have been investigated in detail during Bi determination by hydride generation, both with and without trap in the same HGAAS system. Interferent/analyte (mass/mass) ratio was kept at 1, 10 and 100. Experiments were designed for carrier solutions having 1.0M HNO(3). Interferents such as Fe, Mn, Zn, Ni, Cu, As, Se, Cd, Pb, Au, Na, Mg, Ca, chloride, sulfate and phosphate were examined. The calibration plot for an 8.0 mL sampling volume was linear between 0.10 microg L(-1) and 10.0 microg L(-1) of Bi. The detection limit (3s/m) was 25 ng L(-1). The enhancement factor for the characteristic concentration (C(o)) was found to be 21 when compared with the regular system without trap, by using peak height values. The validation of the procedure was performed by the analysis of the certified water reference material and the result was found to be in good agreement with the certified values at the 95% confidence level.

Gold volatile compound generation: optimization, efficiency and characterization of the generated form

The generation of an analytically useful volatile form of Au has been studied. The flow injection generation was performed in a dedicated generator consisting of a special mixing apparatus and gas–liquid separator design in the presence of surfactants (Triton X-100, Antifoam B) and diethyldithiocarbamate. The on-line atomization in the quartz tube multiatomizer for atomic absorption (AAS) detection has been employed as the convenient atomization/detection means. The optimization of generation and atomization conditions resulted in an analytical procedure yielding the detection limit of 17 ng ml−1 and a very good long range reproducibility of the analytical signal. A 198,199Au radioactive indicator of high specific activity together with AAS measurements was used to track quantitatively the transfer of analyte in the course of generation and transport to the atomizer and to determine the generation efficiency of 11.9 ± 0.1% at the Ar carrier flow rate optimized for the multiatomizer of 240 ml min−1. The efficiency was twice as high at the Ar carrier flow rate of 600 ml min−1. In situ trapping in GF for AAS was explored as an alternative to the on-line atomization. The detection limit of 3.0 ng ml−1 was achieved even though the Ar flow rate optimum for trapping (115 ml min−1) was too low for efficient generation: the overall efficiency of generation and trapping was 1.11 ± 0.03%. Transmission electron microscopy measurements proved the presence of Au nanoparticles of diameter of approximately 10 nm and smaller transported from the generator by the flow of carrier Ar.

Aflatoxin species: their health effects and determination methods in different foodstuffs

AbstractCarcinogenic and mutagenic properties of aflatoxin species are known in literature. Their intake over a long time period might be health-dangerous for human even at trace levels. It is well known that different foodstuffs can be contaminated by aflatoxin species through growing and storage. Due to the serious health effects, sensitive determination of aflatoxin species in any matrices related with the human being is very crucial at trace levels. In literature, there are sensitive techniques to analyze the different samples for the contents of their aflatoxin species. Each technique has some advantages and disadvantages over the other techniques. This review aims to summarize the different health effects of aflatoxin species, development of analytical techniques and applications of developed techniques in a variety of matrices.

From mg/kg to pg/kg Levels: A Story of Trace Element Determination: A Review

Abstract Determination of the trace elements in a variety of environmental samples is of great importance. Most elements, including iron, calcium, and selenium, are crucial for the regulation of human mechanisms, and many others, like lead and cadmium, are toxic even at trace levels. Some elements, like selenium, have a narrow margin of safety. Hence, determination of elements at trace levels is crucial in any matrix related to humans. Trace element determination requires sufficiently sensitive procedures to monitor trace levels. This review aims to highlight not only the development in instrumentation for ultratrace element determination in variety of matrices but the application of developed techniques. Advantages and disadvantages of the techniques are also discussed.

Indium determination using slotted quartz tube-atom trap-flame atomic absorption spectrometry and interference studies

Sensitivity enhancement of indium determination by flame atomic absorption spectrometry (FAAS) was achieved; using a slotted quartz tube (SQT-FAAS) and slotted quartz tube atom trap (SQT-AT-FAAS). SQT was used as an atom trap (AT) where the analyte is accumulated in its inner wall prior to re-atomization. The signal is formed after re-atomization of analyte on the trap surface by introduction of 10 μL of isobutyl methyl ketone (IBMK). Sensitivity was improved 400 times using SQT-AT-FAAS system with respect to conventional FAAS and 279 times with respect to SQT-FAAS without any collection. Characteristic concentration (C(0)) and limit of detection values were found to be 3.63 ng mL(-1) and 2.60 ng mL(-1), respectively, using a sample flow rate of 7.0 mL min(-1) and a collection period of 5.0 min. In addition, interference effects of some elements on indium signal were studied. In order to characterize indium species trapped, X-ray Photoelectron Spectrometry (XPS) was utilized and it was found that indium was collected on the inner surface of SQT as In(2)O(3). The accuracy of the procedure was checked to determine indium in the standard reference material (Montana Soil, SRM 2710).

Tellurium speciation analysis using hydride generation in situ trapping electrothermal atomic absorption spectrometry and ruthenium or palladium modified graphite tubes

Speciation of tellurium can be achieved by making use of different kinetic behaviors of Te(IV) and Te(VI) upon their reaction with sodium borohydride using hydride generation. While Te(IV) can form H(2)Te, Te(VI) will not form any volatile species during the course of hydride formation and measurement by atomic absorption spectrometry. Quantitative reduction of Te(VI) was achieved through application of a microwave assisted prereduction of Te(VI) in 6.0 mol/L HCl solution. Enhanced sensitivity was achieved by in situ trapping of the generated H(2)Te species in a previously heated graphite furnace whose surface was modified using Pd or Ru. Overall efficiency for in situ trapping in pyrolytically coated graphite tube surface was found to be 15% when volatile analyte species are trapped for 60s at 300°C. LOD and LOQ values were calculated as 0.086 ng/mL and 0.29 ng/mL, respectively. Efficiency was increased to 46% and 36% when Pd and Ru surface modifiers were used, respectively. With Ru modified graphite tube 173-fold enhancement was obtained over 180 s trapping period with respect to ETAAS; the tubes could be used for 250 cycles. LOD values were 0.0064 and 0.0022 ng/mL for Pd and Ru treated ETAAS systems, respectively, for 180 s collection of 9.6 mL sample solution.

Recent Advances in the Synthesis and Applications of Inorganic Polymer

Polymers are ubiquitous in modern society. They are used in a variety of applications, ranging from sophisticated—such as electronics—to relatively simple ones like packaging. Inorganic polymers often have certain advantages over their organic counterparts—such as increased thermal stability and unique material properties—and have been an active area of research for many years. The potential technological applications that are imagined for some of these polymers, however, have mostly failed to be realized. This article aims to examine some of the advances in the general field of inorganic polymers, which have been made in the last three years. We also attempted to ascertain whether the promise of these materials will be realized in the near future, especially as advanced polymeric materials.

Determination of Copper in Water and Walnuts by Solid Phase Extraction and Slotted Quartz Tube Flame Atomic Absorption Spectrometry

ABSTRACT Cu(II) was separated and preconcentrated using solid phase extraction and a slotted quartz tube (SQT) and determined in drinking water and walnuts by flame atomic absorption spectrometry. The procedure is based on the sorption of copper(II) on a column filled with a resin followed by elution with 5 mL of 3 mol L−1 nitric acid in the first preconcentration step. To increase the sensitivity of system, the preconcentration parameters for copper(II) were optimized. The SQT was used as the second preconcentration step to further improve the sensitivity. The enrichment factor and detection limits were 640 and 0.23 µg L−1, respectively. Another advantage of this method is the presence of a wide pH range for copper(II) sorption with high effectiveness in acidic media. The accuracy of method was confirmed by the analysis of a spinach leaves certified reference material (NIST 1570a).

Determination of Sulfur in Grape and Apricot Samples Using High-resolution Continuum Source Electrothermal Molecular Absorption Spectrometry

The determination of sulfur in apricot and grape samples was performed by using high-resolution continuum source electrothermal molecular absorption spectrometry based on vaporization of the carbon monosulfide (CS) molecule. CS forms in the gas phase without the addition of any molecule-forming element, since graphite cuvette contains plenty of carbon as well as food samples. A mixture of 15 μg Pd + 10 μg Mg was used in solution as the chemical modifier. The best sensitivity was obtained at 900°C of the pyrolysis temperature with a K2SO4 calibration solution. The calibration plot drew a linear path between 50 and 1600 ng of sulfur, and the limit of detection was found to be 23 ng. The accuracy of the method was confirmed with the use of a standard reference material (Rice Flour, NIST SRM 1568a). The sulfur content in chemically dried apricot samples (1987 ± 45 mg/kg) was determined to be higher than that of apricot samples dried under sunshine.

Determination of Adsorption Characteristics of Orange Peel Activated with Potassium Carbonate for Chromium(III) Removal

In this study, Cr (III) removal from aqueous solutions was investigated by using the batch adsorption method. An orange peel activated with potassium carbonate (OPAPC) was used as the adsorbent. In order to determine optimum adsorption conditions, adsorbent concentration (2-15 g/L), pH (3-7), temperature (298-318 K), contact time (10-270 min) and initial concentration of Cr (III) (5-50 mg/L) were investigated for Cr (III) removal from aqueous solutions using OPAPC. The equilibrium data were evaluated using the Langmuir and Freundlich model equations and the kinetic data were evaluated with pseudo first and second order kinetic models. In addition, the adsorption thermodynamics of the proposed method in optimum conditions was investigated.